Prop Help

[mflynn3401]

Have a 21' Stingray with 4.3L 190HP. Currently have a 3 blade 14.5 x 19 which pulls good for water sports. Boat runs about 4900 RPM at WOT which is above the recommended 4400-4800 at about 40 MPH. Wanting to switch to a 4 blade prop and slightly reduce WOT into range. Wanting to keep pulling power for water sports but wouldn't mind a couple extra MPH on the top end. Debating between a 4 blade 14 x 19 or a 4 blade 14 x 21. Thoughts?

 

[superbenk]

Adding a blade won't get you any speed. In fact you'll probably lose a little top-end with the additional blade since that extra blade adds drag.

Also, adding another blade will also drop your engine RPM slightly. I'd probably stick with the 14x19 if you're switching to a 4-blade. Maybe a 14x20 makes better sense with the 3-blade?

 

[Sea Rider]

Stay with current prop. +100 wot rpm over revving as currently loaded is nothing, just throttle bit less or add slight more weight if like running full hammer down. There's nothing to better, prop is spot on.

Happy Boating

 

[Faztbullet]

Just have some cup added to blades,will drop RPM and increase top a tad...